Persistence. Focus: Treatment and Medico-legal Issues 3 rd Jack Pepys Workshop

1. Persistence.Focus:Treatment and Medico-legal Issues3rd Jack Pepys Workshop Susan M Tarlo University of Toronto University Health Network and Gage Occupational and Environmental Health Unit

2. Disclosures • Patients are seen for medical assessment at the request of the Ontario Workplace Safety and Insurance Board (WSIB), approx 1 new patient per week • Patients referred by other physicians may have claims submitted by me to WSIB • Files being appealed from WSIB may be reviewed for an independent medical opinion from WSIAT • Research funding has been received from WSIB RAC

3. From 100 questions/needstreatment/medicolegal 77. Despite strong medical advice to discontinue exposure to a work sensitizer, some patients with OA continue to work in the same environment with the same or reduced exposure. What is the value of inhaled steroids in such patients? 78. Subjects with OA are exposed to common allergens after being removed from work. In the case of OA due to low molecular weight agents, is there cross-reactivity with other common environmental chemicals that resemble the causal agent? 79. In aiming to assess the efficacy of intervention in work-related asthma, a problem in the design of post-intervention studies is that there is usually no control group. How can this study design problem be overcome?

4. Current management of sensitizer-induced OA during/post diagnosis • Initiate appropriate compensation claim (early) • Control the asthma - throughout • Evaluate and control exposure to relevant non-occupational triggers • Asthma medications as per guidelines • Evaluate appropriate work accommodation • For the patient • Consider co-workers and possible work intervention to protect other workers

5. Evaluate appropriate work accommodationfor the patient when the sensitizer is known • Where possible, completely avoid further exposure to the relevant sensitizer after diagnosis • If impossible for socio-economic reasons, reduce exposure – compensation issues may be relevant here – if this is the required approach, either pending a compensation claim or for other reasons such as lack of eligibility for compensation, there must be careful medical monitoring, and further intervention if asthma is worsening

6. Exposure ManagementAHRQ Evidence Report #129, Nov 2005, Beech et al • 52 cohort studies • Due to vagaries of reporting, statistical analyses of published studies not feasible • Graphic display of results suggested worse outcomes (FEV1 and methacholine responsiveness) for those remaining at work vs those removed. No clear difference in trend for HMWt vs LMWt sensitizers

9. Black= HMWt White=LMWt Grey=mixed/unknown PC20 changes

10. Possible measures to avoid/limit exposure Best to worst options • Avoidance – complete - change of process, e.g. non-latex gloves, enzyme change, paint change Change of work area/workplace (with review of exposures in new area) • Partial reduction e.g. low-protein, low powder latex Move to low-exposure area Improved occ hygiene measures, e.g. ventilation/exhaust Improve resp protection

11. Outcome with removal vs continued exposure (Moscato et al Chest ’99) • 25 with OA confirmed by challenge, followed for 1y • 13 left exposure – significantly worse asthma at diagnosis, FEV1 and PD20 • At 1y those who left had improved more than those who stayed – decreased medication needs vs increased needs in those who stayed • However only those who left had a loss in income (>25% median loss)

12. Inhaled steroids for those who cannot avoid exposure(Marabini et al Chest ’03) • 20 subjects with OA (mean sx 13+/-13y), still working. 12 moderate, 8 mild • 3 y f-up, protective equipment as able • 10 retired/changed jobs (significantly younger than those who stayed). Only 2 cleared • Those who stayed were treated with high dose inhaled steroids and bronchodilators • No statistically significant change over the 3y in spirometry, bd needs for those who stayed, • PD20 mg yearly mean: 1.4, 1.3, 1.2, 0.8 (NS) Findings limited by small numbers. Trends to decline in PD20. ?? Whether applicable to those with earlier diagnosis

13. Reduced exposure for NRL-OAAsthma symptom scores (ASS) and histamine PC20 Vandenplas et al JACI 2002

14. Monitor asthma closely with occupational changes (changes in exposures/job) • When the sensitizer is unknown and/or may be present in a new environment • When there may be cross-reacting agents in the environment where the patient is moved to • When the exposure is reduced but not eliminated Symptoms/medications/pulmonary function parameters/? NO, ? induced sputum

15. Cross-reacting agents • Other than similar chemical sensitizers, e.g., other diisocyanates in or out of the workplace, little published data on agents cross-reacting with work-sensitizers • - a few older reports of colophony and non-occupational pine products ? Any current research in this area

16. Pharmacotherapy • Inhaled steroids – 2 older clinical trials suggested benefit, no recent trials • No recent studies of pharmacotherapy among those remaining in exposure

17. Immunotherapy? • Small trials of immunotherapy have been reported for NRL allergy and asthma • Benefit found more for nasal/eye symptoms than for asthma to date (Sastre et al, JACI ’03) • Sublingual treatment appears to be better tolerated but local reactions(89% patients) and systemic reactions (46% patients) were still common (Cistero Bahima et al J Invest All Clin Immunol ’04) Not considered standard treatment for OA

18. Immunotherapy with other agents • Beekeepers with anaphylaxis (± asthma) respond well to venom immunotherapy (Muller, Curr Opin All Clin Immunol 2005) • Armentia ’90 assessed 30 bakers with wheat immunotherapy (20 active, 10 placebo) with significant benefit – no recent studies • Common allergens, cat, pollen, not specifically addressed in OA • Omalizumab not reported as yet for OA

19. Some reasons for poor medical outcome • Severe asthma at diagnosis • Late diagnosis (2◦ to patient or physician), delay or no compensation: leading to prolonged exposure • Occupational factors • Ongoing exposure to the work sensitizer or cross-reacting agents (known or unknown) at work or in other environments • Workplace irritant exposure aggravating asthma • Other contributing factors • Non-occupational allergen exposure/ irritants • GERD, VCD, non-asthma causes of symptoms

20. Compensation/medicolegal issues • Different systems in different provinces, states, countries • Some issues likely to be common in many regions where others may be specific • Criteria for acceptance may differ - e.g., need for SIC for OA, acceptance of WEA • Process might contribute to persistence of asthma/disability – no identified published data on this More likely if workers continue exposure because: Ineligible for compensation Reluctance to apply for a claim – no data Delays in a claim decision – could be years

21. E.g., Ontario WSIB www.wsib.on.ca • Began 1915 as WCB • Financed by employer premiums (adjusted by risk) • No-fault collective liability: workers give up their right to sue • 1998 Changed name to WSIB and mandate changed to include promoting prevention of work-related injuries and illnesses. It now also oversees Ontario’s system of workplace safety education and training, and supports research via an independent Research Advisory Council and Centres for Research Expertise, e.g. CREOD. • Mandate includes disability benefits, monitoring quality of healthcare, and assisting in early safe return to work

22. Ontario WSIB • Policy: In determining a claim the decision shall be made in accordance with the real merits and justice of the case. ..When the evidence for or against the issue is approximately equal in weight, the issue shall be resolved in favor of the person claiming benefits (not to be used as a substitute for evidence). • Decisions on claim acceptance and compensation made by claims adjudicators – they are usually assigned by work sector rather than by disease/injury. They can get advice from the “complex case unit” WSIB physicians who may request additional external independent medical assessments, e.g., from the occupational disease specialty program. WSIB pays for costs of assessments/investigations.

23. Support provided for accepted OA claims • Economic loss - 85% provided for limited time after claim accepted if further job is feasible, supplement if lower-paying job obtained • Cost of medications/medical devices • Non-economic loss: disability (usually assessed at the time of considered maximum medical recovery, e.g. often 1-2 y after an OA claim is accepted). Includes disability from asthma plus disability from sensitization if present. • Training for new work if approved – labor market re-entry skills, re-training (secondary/post secondary ed) • Examples: 18 y old baker, 45 y old plasma welder

24. Work-exacerbated/aggravated asthma • Policy: “In cases where the worker has a pre-accident impairment and suffers a minor work-related injury or illness to the same body part or system WSIB considers entitlement to benefits on an aggravation basis.” • “Generally entitlement is for the acute episode only and benefits continue until the worker returns to the pre-accident state.” • Entitlement is not limited when there is no pre-accident impairment or if the severity of the exposure/accident on its own would have resulted in additional impairment – i.e. potential for “permanent aggravation” • Aggravation is the effect that the injury/illness has on pre-accident impairment, requiring healthcare and/or leading to loss of earning capacity – can include permanent impairment

25. Compensation issues • Not all workers are covered • Processes for decisions and levels of compensation differs widely between and even within countries • Process can be complicated and time-consuming for workers and physicians – forms for worker/physician/workplace • Decisions can take months to years • Workers with OA often do not have skills to transfer to other similar-paying occupations • Job-market re-entry programs may provide some skills but will usually not find replacement work, and self-found jobs may pay less than former work

26. More compensation issues • Workers may lose non-compensated benefits from previous job, e.g. dental plans, general medication coverage • Even with accepted workers’ compensation claims, significant socio-economic loss is reported • Effects of having a previous compensation claim on chance of employment, not published • Some workers are reluctant to accept advice to initiate a compensation claim and prefer to continue working with OA as long as possible – may lead to less reversibility and greater long term asthma morbidity • Suggests that further improvements are needed for compensation issues

27. Ontario WSIB appeals • Worker or workplace can appeal decision to WSIB – issues of stress, income loss • Next decision can be appealed to an independent Workplace Safety and Insurance Appeals Tribunal an agency within the Ontario administrative justice system who may ask for further independent medical review

28. Conclusions • Early diagnosis and removal from further exposure (for sensitizer-OA) offers best medical outcome - but often at a significant socio-economic cost despite workers’ compensation systems. Other management options (e.g. greatly reduced exposure for NRL), are an alternative for some agents and are selected by other workers with OA against medical advice. • Immunotherapy may benefit some patients but few allergens have been assessed and monoclonal anti IgE has not been assessed. Pharmacotherapy + reduced exposure has not currently been proven of benefit • The effects of compensation systems on asthma persistence have not been documented